Science and technology

Pathology

Reviving autopsy

TECHNOLOGY advances not only through new inventions, but also by the imaginative application of old ones. And one of the most ancient forms of scientific investigation, the post-mortem autopsy, may be ripe for just such a technological upgrade. According to a paper in this week's Lancet, published by Ian Roberts of the John Radcliffe Hospital, in Oxford, it may soon be time to put away the scalpel and the retractor clamp, and to replace them with the body scanner.

The study of death is never a cheerful topic, but it has gone through a particularly gloomy patch over the past few decades. A recent tally by America's Centres for Disease Control and Prevention showed that in 2007 only 8.5% of deaths in America were investigated by autopsy. In 1972 that figure was 19.3%. Britain's coroners are more active, but perhaps not more accurate. Twenty-two percent of deaths in the United Kingdom lead to an autopsy. According to a government review, however, one in four is of miserable quality. The upshot in both cases is not just that the cause of individual deaths may be misascribed. More seriously, data about the processes of disease are lost, and those diseases are thus not as well understood as they might have been. Squeamish relatives of the deceased, too, often do not like the idea of bodies being cut up at the behest of coroners. Britain's health department therefore commissioned Dr Roberts to study whether scanning dead bodies in the way that is routine for living ones would help. His conclusion is that it would.

Rather than slicing the body with a knife, scanning slices them with radiation. Computerised tomography (CT) uses X-rays to collect information from many angles, and a lot of processing power to convert that information into cross-sectional images of a body's inner tissues. In forensic cases CT scans are often used to spot fractures and haemorrhages. Dr Roberts found them adept at noticing diseased arteries, as well. The other widespread scanning technique, magnetic-resonance imaging (MRI), uses radio waves and is best suited for exploring the detail of soft tissues.

Though both of these technologies have been around for a long time, they have had only limited use in autopsies. America's authorities conduct CT scans of dead soldiers—but such scans are employed to augment traditional post mortems, not replace them. Some coroners in England, spurred on by the religious objections of Jews and Muslims, do allow scans rather than conventional autopsies in certain cases. But the accuracy of these scans is unknown. Dr Roberts is the first to provide data on whether scanning might replace conventional methods.

He and his colleagues examined 182 bodies in Manchester and Oxford. Radiologists studied CT and MRI scans of these bodies, made diagnoses based on them, explained their confidence in these diagnoses, and judged whether the scans might thus preclude the need for a full autopsy. Within 12 hours of each scan, a pathologist then performed a conventional autopsy, so that Dr Roberts could compare the new methods with the old.

The scans were far from perfect. The rate of discrepancy between the cause of death, as determined by radiology and as determined by conventional autopsy, was 32% for CT scans, 43% for MRI and 30% for a combination of CT and MRI. Most troubling, the scans had difficulty showing heart disease, a common killer. However, radiologists were good at identifying which diagnoses were sound and which needed to be re-evaluated by a full autopsy. When they felt confident in their diagnoses—which was the case for 34% of CT investigations and 42% of MRIs—the discrepancy between the results from scanning and those from autopsies was lower. For CT scans, it was just 16%.

That is still a significant gap, of course. But not all of it is caused because traditional methods are better. For one body, for example, scanning revealed a lethal stroke that dissection missed.

All this suggests that scans might play a useful role in determining causes of death. When a radiologist is confident in the diagnosis from a scan, a traditional autopsy might be unnecessary. When he is less confident, his scan could still be a useful guide for the wielder of the knife.

Automating autopsies by using scanners might also make them cheaper, by speeding the process up. And it could be done with otherwise-redundant machines that have been replaced for use on live patients with modern devices which give off less radiation. That would get rid of the need to buy new kit to cope with the extra demand for scans. A thorough study of the costs of both approaches would be needed, of course, and traditional autopsies are unlikely to disappear completely. But for some deaths, a scan will likely prove better than a scalpel.

A deceased may have Stage 4 Metastatic Lung Cancer but the actually cause of death may have been sepsis due to a bladder infection in a weakened malnourished state with a suppressed immune system in a bed bound patient.

The CT only shows the advanced tumor, not the process of expiration, loss of mobility, decline in health, loss of function, and bacteremia.

The exact cause of death is usually multifactorial with several contributing factors all intertwined in a downward spiral. A good general term for interns is "Multi-Organ Failure" --it covers the bases.

And the major diagnosis at the time of expiration, though simplified, is the principal cause.

Radiology reveals the Principal Pathology Diagnosis. The Exact Cause of expiration is usually related to air way, cardiac, volume management, shock, sepsis or multiorgan failure.

I would advocate a last post-mortem CT Scan. It would take less than 30 seconds--less time than it would to re-make the bed with fresh linen. There is no risk to the expired patient. The images are exceptionally crisp since there is no motion or breathing artifact. The flesh is not violated. It may be read or left uninterpreted for future science retrograde studies to look at advanced cases of a condition.

I'm not sure that "cause of death" is the important result from autopsy. Understanding the course and progress of disease in people is the goal, not labeling a particular death. As Connect the Dots notes, diseases and conditions have complicated effects on the body. A cause of death as "heart failure" doesn't say much if the person's heart failed due to a disease.

I can't get the Lancet article online yet, but the Economist story makes it sound like it WON'T be time to put away the scalpel any time soon -- postmortem CT and MRI missed 30-40% of diagnoses that autopsy detected. At this point, it is a nice complementary technique but by no means a replacement.

Being a pathologist, I'm a bit biased on this matter, but in my opinion, an autopsy is the last, best chance that medicine has to understand the series of events that led to a person's death. Why compromise that ability by electing not to use the best tools available?

It seems that one system over another should not be favored. Both, manual autopsies and ones done with scanning have merit in different ways and each works best for different cases. Neither should be completely thrown out, instead the two should be worked side by side. The combination of the two could have greater results than either one of them could by standing alone.

Wonderful work by Ian Roberts ,there is certainly something in here.It is amazing how a process once it is described then seems so obvious that one then has to scratch one's head and say 'Why did'nt I think of this one !'.A brilliant idea all round,and once all the teething problems are ironed out I am sure it would be the way forward.

Being able to use a machine to tell the cause of death and time would be very helpful in investigations, crimes, and further medical research. If radiologists can continue to produce such efficient machines and scans, then medical testing and so much knew knowledge of causes of death would be able to be determined.

Good idea. Such CT scan data could also be contributed to an anonymous database, perhaps augmented with a tissue and/or DNA microarray (or eventually sequence) dataset on the individual. Over time, the accumulation of such data would surely be helpful to the successful correlating of risk factors, causalities and health outcomes. If this information were also combined with the individual's cumulative health record, including diagnoses, therapies and such, a rather valuable reservoir of "probabilistic diagnostic" and research information might result. Perhaps individuals should be offered the option to be a "data donor" as well as an "organ donor" in the case of their death?

Seems one sure way to make a useful contribution to humankind upon leaving this world.

When the cause of death is completely unknown, I think that the scans would be exremely helpful because they could show an over view of the body. This might help lead to the general area where the cause of death was, rather than someone having to slice open every area of the body searching for the cause first thing. Pictures, however, are never as good as hands on material.

jennb924,are you trying to protect your job perhaps, as a pathologist ? Once the system Ian Roberts is proposing is ironed out and perfected, then pathologist and coroners are going to have to work differently.That is certainly going to happen you have been warned.

I think this is a great idea to start incorporating scans into finding the cause of death in people. If this was used initially instead of using the time of a doctor, causes of death could be discovered much quicker. I also really like the idea of using older scanning equipment for these bodies because of the lack of concern with radiation. That would really put these older machines to good use as I'm sure they would be much cheaper to purchase than brand new equipment.

CT scanning could well be a useful adjunct to conventional autopsy, but it cannot replace it. CT has a finite resolution much greater than that of the naked eye, it cannot see colour changes, smell, or feel texture. CT cannot take samples of tissue for histological or microbiological analysis. Lots of sick patients who die in hospital have had multiple scans in the days leading up to their death: frequently a physical autopsy is required to provide satisfactory answers.

There is also the issue of cost and infrastructure. In the UK old CT scanners are typically sold off and replaced directly with a new machine. A CT scanner does not operate in isolation, but requires a large, specially shielded and air-conditioned room, with an adjacent control room, associated electronic hardware and software etc. Most hospitals, in the UK at least, do not have decant rooms for decommissioned CT scanners: space is precious and these rooms are very expensive to build. Even an old machine requires revenue for servicing, spare parts, quality assurance, radiographer and radiologist time. It may well be less expensive to use contemporary kit. Working out how to fit a macerated cadaver in with a list of breathing patients will be interesting.

CT scan implementation for autopsy is one of the advanced tools in forensic investigation. A forensic radiologist rather than a clinical radiologist would prove the scan to be worth in concluding the cause of death. Analysis of the data with 3D, 2D and MPR not only allows the forensic pathologist to determine the cause of death, but also the motion dynamics of the fractures and pattern of injuries. The 3D visualization plays a keys roll for the interpretation of motion dynamics of the fracture and its required to use a forensic specific software tool for 3D rendering rather than the clinical 3D visualization tool. Malaysia has been using the CT autopsy with forensic specific 3D rendering toll along with the classical autopsy

femi, unfortunately the system that roberts is proposing can never be "perfected". Imaging a tissue will *never* be superior to gross or microscopic exam of the tissue. CT can give certain information that can supplement the findings of autopsy, but examination of the tissue is necessary.

We've been using ct for all our autopsies at the Section of Forensic Pathology here in Copenhagen, Denmark since 2003. Obviously it's great for ballistic cases, traffic and certain natural deaths but there are limitations that so far can't be determined without an autopsy. We use it for preparing the autopsy better, for documentation, research, identification etc. but we think that autopsy in many cases are still needed.
I do strongly support that more forensic departments will get the chance to have their own scanners and if the case load is too big to scan all cases, then at least scan the traumas etc.